Well, it took a while but Matt Lukes has created a very fine example of this rare bronze helmet.

I'm pretty happy they way it turned out and expect the Indians to offer copies soon - so if you want one, just be patient

More background:
Source:
TOPOGRAPHIC SEMANTICS: The Location of the Athenian Public Cemetery and Its Significance for the Nascent Democracy
Author(s): Nathan T. Arrington
Source: Hesperia: The Journal of the American School of Classical Studies at Athens, Vol. 79,
No. 4 (October-December 2010), pp. 499-539
Published by: The American School of Classical Studies at Athens

Page 530.
"Two more burials near the Leokoriou Roads also deserve mention for
their hippie associations. At Madytou 11 (H 1) near Hippios Kolonos, in
the Late Classical period, a man was buried in a marble cist with an iron
sword on his chest, a bronze petasos helmet at his feet, an iron strigil, and
two alabastra. Helmets of this type are usually worn by cavalry. The grave
also contained several bronze discs and other objects that may have been
ornaments for a horse or rider.171 Athenian Classical burials with armor
are extremely rare; indeed, I know of no other inhumation in the entire
area northwest of Athens that contained weapons or armor, with the
exception of the arrowheads in the Tomb of the Lakedaimonians."

Joe, I'm very jealous of your petassos helmet! Well done!
The original seems to have perforated edges (confirmed?). Someone had interestingly suggested that it might have had a felt cover on its outsider ao that it looked like an ordinary petasos with a bronze interior. Another possibility is that it had a leather or felt interior. A leather edging in my opinion would disrupt the nice shape of the helmet and add no benefit in such a wide brimmed hat.
Khaire
Giannis

"And the four bare walls stand on the seashore. a wreck a skeleton a monument of that instability and vicissitude to which all things human are subject. Not a dwelling within sight, and the farm labourer, and curious traveller, are the only persons that ever visit the scene where once so many thousands were congregated." T.Lewin 1867